Where and how did the word knot for boat speed come from?

Question

Where and how did the word knot for boat speed come from?

Answer 1

I believe I actually know the answer to this....It was first derived back in the day when a rope was tied into knots and lowered down into the water and as each knot passed thru there hands it was calculated to how fast the boat was going.  Something to that effect...lol!

Answer 2

In the ancient times, the only way to measure ship speed was to throw a wood log into the water and observe how fast it moves away from the ship. This approximate method of ship speed measurement was called 'Heaving the Log' and was used until 1500-1600s when the 'Chip Log' method was invented (both methods probably invented by Dutch sailors.)

The 'Chip Log' apparatus consisted of a small weighted wood panel that was attached to the reel of rope, and a time measuring device: a half-minute sand glass (as shown in image below to the right.) Rope had knots tied at equal distances along the reel. Sailors would throw the wood panel into the sea, behind the ship, and the rope would start unwinding from the reel. The faster the ship was moving forward the faster the rope would unwind. By counting the number of knots that went overboard in a given time interval, measured by the sand glass, they could tell the ship's speed. In fact that is the origin of the nautical speed unit: the knot.

Answer 3

Knot is short for nautical mile which is roughly 1.1 mph According to Wikipedia this is the origin: In some sailing ships, speed was measured by casting the chip log from the stern. The log was relatively immobile, and attached by line to a reel. Some sources suggest that knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another used a 28 second sandglass to time the operation.[citation needed] The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km·h−1. The difference from the accepted value today is a bit less than 0.02%.

Answer 4

It's based on the practice of observing a knotted log line, or line tied to a floating piece of wood, to measure speed.

In some sailing ships, speed was measured by casting the chip log from the stern. The log was relatively immobile, and attached by line to a reel. Some sources suggest that knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another used a 28 second sandglass to time the operation. The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km·h−1. The difference from the accepted value today is a bit less than 0.02%